Numerous specific strains of laboratory mice are utilized as research models. However, immediate research needs for certain murine genetic types varies considerably. This often results in the excessive expense of maintaining many breeding animals from a certain strain which may or may not be valuable for future investigations. One alternative is the freeze preservation of embryos, which at a later time, can be thawed and transferred to recipinet dams, thus perpetuating specific strains. In this study the techniques necessary to collect, freeze, thaw and surgically transfer mice embryos are being developed. Such procedures will eventually be used to more economically manage and store invaluable genetic stocks to ensure availability for future research investigations.